pope benedict is spending his last night as pope. and the mysterious figure looks out on st. peter's square, before, seconds later, those lights go out. now, only hours until the leader of 1 billion catholics steps down and returns to his life outside the spotlight. so, let's begin in st. peter's square with "good morning america" co-anchor george stephanopoulos starting us off. george? >> reporter: diane, history was made here in st. peter's square today. no one has ever seen a pope say good-bye like this.